As described within Italian Patent No. 1,097,695 of Illinios Tool Works Inc, entitled "BUCKLE", the necessary parts of which are incorporated herein by reference, there is disclosed a buckle comprising a male part having a device for gripping a strip or sheet material, such as, for example, a belt or braces, and a base shoulder from which project a pair of resilient lateral arms and a rigid central arm, the arms together forming an E-shape configuration. The buckle further includes a female part defined by means of a box-like body, having a frontal opening and a pair of lateral through slots defining within it a housing socket for receiving the male part. The female part is also usually provided with a device or component portion for gripping strip or sheet material, and is also usually further provided with guide means which, during the connecting operation defined between the male and female parts of the buckle, cooperate with the rigid central arm of the male part for guiding the movement thereof and, once the connection has been achieved, which takes place by means of the snap-engagement of respective teeth or projections carried upon the resilient arms of the male part respective with the slots of the female part, limit the possible displacement of the male part to movement within a single plane and further act to reinforce the central arm of the male part by providing it with a continuous abutment in such a way that this latter component is, in use, adapted to limit any possible deflection of the resilient arms of the male part inwardly with respect to the female part, such as, for example due to the transmission to the buckle of torsional forces, and thus avoids accidental release of the buckle.
Buckles of the type described operate very well and have a considerable ease of use. However, as has been noted particularly in recent times, the requirement has arisen for making the release of the buckle particularly rapid. Furthermore, buckles of the type described have a coupling position established by means of the cooperation of the base shoulder of the male part with the mouth of the socket of the female part. In order to allow connection and release of the buckle, this position must be established in such a way as to leave a small axial clearance for the teeth or projections of the male part disposed within the slots of the female part so that, under particularly loaded and unstable conditions, such as for example buckles used for harnesses for sporting activities (surfing, sailing, or the like) and/or for helmets, a predetermined amount of wear of the connecting parts arises or develops after a predetermined period of use.